import random
checkcode = ''
for i in range(4):
    index = random.randrange(0,4)
    if index != i and index+1 != i :
        checkcode += chr(random.randint(97,122))
    if index+1 == i:
        checkcode += chr(random.randint(65,90))

print("当前验证码为：",checkcode)
